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Forum Index : Windmills : help i’m clueless

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poorman

Newbie

Joined: 10/05/2009
Location: United States
Posts: 9
Posted: 12:41am 10 May 2009
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I'm looking into building a windmill and have a bunch of "undiscovered treasure/junk" laying about I'm wondering if you can turn an ac motor into a generator if I'd have to re-wind it add magnets or a vaccum cleaner motor?
Do not worry about your difficulties in mathmatics. I can assure you mine are still greater..... Albert Einstein.
 
niall1

Senior Member

Joined: 20/11/2008
Location: Ireland
Posts: 331
Posted: 01:53am 11 May 2009
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Hi poorman
just speaking as another poor man.. ... i havent come across any easy mod or reasonably cheap off the shelf alternator /generator that will work (depending on your needs)...re-winding ...adding mags to an ac motor is a bit of a black art and your own machine shop would be a big advantage .....
dont let that put you off though ... necessity is the mother of all invention

permanent magnet motors /alternators (pma,s) is a good starting pointEdited by niall1 2009-05-12
niall
 
oztules

Guru

Joined: 26/07/2007
Location: Australia
Posts: 1686
Posted: 01:16pm 11 May 2009
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Hmmm,
You can generate power with anything that has got wire in it and a magnetic field that cuts it.... and you don't inadvertently cancel out the coils..

That said, there is a huge variation in results with different contraptions. You need to identify why you are doing it in the first place , to try and work out what you have to do to get your level of output.

If you wish to replace the grid, you will need to be on acreage somewhere with a good wind regime. a big tower and a big well designed/getting quite expensive machine.... and all the paraphernalia that goes with it (16000 dollars or so for a start) otherwise if your in an urban environment... forget it.

If you wish to experiment with wind, and just want to generate some power.... just to watch, and maybe power a few small things when everything is going your way, then the sky is the limit. If your in an urban environment, then a small fangdangle is about all you will be able to manage without being thrown out of town.

As a rule, vac motors will generate power... but not enough to charge anything, and will probably cost more power supplying the magnetizing power for the field than it will ever be worth, but as an experiment is ok....

If you were keen you could cut off the commutator, and replace with slip rings, rewire the armature to a 2 pole device, and use the field coils as your ac output.... a little 800mm blade and were off....well you still need to drive the slip rings with power... but then were off.... well we may need to gear it up too... but now were off.... well not quite, we need a controller to provide power to the sliprings, and we need to be spinning before we do it.... a little thing called cogging..

Of course you could replace the armature winding with magnets, and use that .. now you will really know what cogging is... Vac motor... curiosity only.

A car alternator will do a bit better, and you can replace the armature with magnets ( or even a big donut magnet pressed in where the rotor coil was, with a stainless shaft)... but will still need gearing to perform well.... or rewire the field basket, this will get the voltage up at low revs, but poor current... no-one said it was easy??... cogging will still be a problem though with the magnets..... now we can always pull the stack apart and stagger the plates and then rewire... now we only have iron loss.

Now that is what experimenting is about using junk. There will be no fiscal reward, but would be interesting just the same. Your other junk falls into the same category. All kinds of schemes can be hatched to make power, but just how much is the key.

Induction motor (AC induction motors) are the next step up the scale, and are quite economical to do magnet wise, but the machining is problematic without your own well equipped workshop. You may get a KW out of the larger motors, but you will be well out of town to do it.

The F&P washing machine motors are a good junk unit, which with little extra work, can be pressed into service to generate small but usable quantities of electricity, but your up in the 8' and beyond range to do this. So a tower, and neighbors and council may be a problem. These things are the closest I think you will get to a piece of junk that is a useful performer and there is a huge reservoir of info on this site just for these things..

Next up the list in power.... you need to spend some time and money, and make a machine from scratch. The rewards will be higher, but so will the expense, and the real estate to warrant building it.

If you want lots of power you need lots of wind, and room to use it, and an expensive device. If you just want to dabble, it can be an inexpensive hobby, with hours of pleasure, using junk cobbled together into a working mill.... but you won't be generating lots of power.... but it will be your power.

Sadly, all that is just the start, next will be matching your new alternator to a blade set.... I mean matching.

Then a tower, a battery bank, a rectifier and diversion controller, and last but not least, an inverter to match.

The junk is barely the beginning... but it's fun



..........oztules

Edited by oztules 2009-05-12
Village idiot...or... just another hack out of his depth
 
poorman

Newbie

Joined: 10/05/2009
Location: United States
Posts: 9
Posted: 02:08pm 11 May 2009
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ok so i have this one motor its a 3/4 hp capacitor start ac motor and i have a lot of time five acres of property in the middle of nowhere texas i have plenty of wind and can access pretty much any tools i could need and scrap wood metal and pvc are easily located cheaply. is it possible to make a decent windmill with this and what would be the first step?
Do not worry about your difficulties in mathmatics. I can assure you mine are still greater..... Albert Einstein.
 
oztules

Guru

Joined: 26/07/2007
Location: Australia
Posts: 1686
Posted: 02:43pm 11 May 2009
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An interesting place to start is here:

Hopefully Dinges will chime in and tell us where his excellent tutorial is now located. It is not where that thread pointed to.


........oztules
Village idiot...or... just another hack out of his depth
 
Dinges
Senior Member

Joined: 04/01/2008
Location: Albania
Posts: 510
Posted: 03:59pm 11 May 2009
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Oztules, the decogging tutorial can be found here:

http://www.otherpower.com/images/scimages/3538/decogging_tut orial_V1.pdf

The tutorial only deals with a small subset of the problems in making a conversion (building a permanent-magnet rotor); before reading it, I'd strongly suggest to read these documents by Zubbly too, as they deal with other aspects of conversions: (can't find them; always had trouble finding these 3 files in the mess that Fieldlines is; maybe another user has the link to Zubbly's 3 PDF-files on converting motors).

Also, read everything else written by him:

http://www.fieldlines.com/user/uid:253
http://www.fieldlines.com/user/zubbly/diary
http://www.fieldlines.com/user/zubbly/stories

I'm not sure why you already seem to have decided on building a motorconversion. As I read your post I'm not sure you're aware of the alternatives (axial flux generators, F&Ps, small DC motors) or the downsides of conversions. Not sure what your goals are either: to have a bit of fun using junk you happen to have, or to power the house. Depending on your needs the AC motor may need or not need a rewinding as well. Anyway, before going any further you'd do well to read this page too. Should probably be the nr. 1 thing to do now:

http://www.otherpower.com/otherpower_wind.shtml

This one is excellent too:

http://www.thebackshed.com/Windmill/Contents.asp

Not to discourage you in your new-found interest of windturbines, but the title of your post is 'help I'm clueless'. In that case there's really only thing you must do first: lose the cluelessness. There's a lot of info out there, but it takes time and effort to digest it all. No one else can do that for you.

Peter.Edited by Dinges 2009-05-13
 
Janne
Senior Member

Joined: 20/06/2008
Location: Finland
Posts: 121
Posted: 06:43pm 11 May 2009
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The zubbly's diary about the motor conversion can be found in pdf format here(among other places i'm sure)

file1
file2
file3
If at first you don't succeed, try again.

My projects
 
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